/Engine/Source/Editor/UnrealEd/Classes/ThumbnailRendering/ThumbnailManager.h
Returns the thumbnail pool which should be used for most thumbnails in the editor.
[TSharedPtr](API\Runtime\Core\Templates\TSharedPtr)< [FAssetThumbnailPool](API\Editor\UnrealEd\FAssetThumbnailPool) > GetSharedThumbnailPool() const